In the production of coating compositions for, among other things, structural building components such as metal building panels, there are often competing goals to be reconciled. On the one hand, there is the need for good durability properties such as color retention, mar resistance and chalk resistance in the face of severe weather conditions, as well as corrosive industrial pollutants. On the other hand, there is the requirement of good flexibility to facilitate fabrication of the metal without loss of the coating's adhesion.
In the coil coating industry, these difficulties are exemplified by the conventionally utilized plastisol-based coating compositions. Plastisols are desirable coating vehicles in the coil coating industry from the standpoint of fabrication. However, they impart undesirable properties such as poor durability, color retention, chalk resistance and dirt resistance. As a result, compromises must often be made either in terms of ultimate film properties or workability of the coated substrate.
As can be seen from the above, there is a need in the coating industry for a coating system which provides a protective film that not only is durable, but also does not adversely affect the coated substrate's workability and/or ease of fabrication.